With up to a third of adolescents reporting recurrent or chronic musculoskeletal pain, it is a critical national health problem. The experience of chronic pain in adolescence negatively impacts overall health during this important life period, and increases the risk of pain and mental health problems in adulthood. Pain-related fear is repeatedly identified as an important factor that increases the likelihood of poor outcomes among adolescents with pain, and yet pain-related fear is rarely targeted in typical pain management (TPM). Perhaps unsurprisingly, TPM yields no change in pain-related fear, and modest improvements in functional disability. To overcome limitations of TPM for pain-related fear, graded in-vivo exposure treatment (GET) was developed. While TPM focuses on pain control via pain management psychology and impairment-based physical therapy, GET is jointly delivered by a pain psychologist and physical therapist targeting functional improvement, through exposing patients to activities previously avoided due to fear of pain. GET is successful in adults with chronic musculoskeletal pain! and our pilot data of GET for adolescents with chronic pain (GET Living) is robust, with significant declines in patient fear, activity avoidance, and disability. Uniquely, GET Living also targets parent distress and behavior, and our pilot data demonstrate decreases in parent fear, avoidance, and protective behavior. GET Living also distinguishes itself with an innovative assessment approach to patient progress and clinical endpoints. In addition to standard assessment tools, GET Living utilizes electronic daily diary technology to identify exactly when improvements in outcomes are occurring/not occurring, and objective biomechanical assessment using motion analysis and physical activity monitoring via Actigraphy. Building from this work, the proposed research concerns an exploratory randomized controlled trial (RCT) of GET Living aimed at measuring changes in fear and function for adolescents with chronic musculoskeletal pain when compared to TPM. This study will provide necessary findings to support or refute a large multi-site RCT. Aim 1 compares changes in pain-related fear (primary outcome), disability, and parent behavior (secondary outcomes) between GET Living and TPM. Aim 2 characterizes feasibility and acceptability of GET Living to inform implementation of a large multi-site RCT. Treatment of adolescent chronic musculoskeletal pain is suboptimal. Significant breakthroughs require directly targeting mechanisms underlying pain-related dysfunction, such as pain-related fear. Implementing innovative interdisciplinary outpatient treatment that addresses pain-related fear and dysfunction, coupled with proof-of-concept electronic daily diaries and biomechanical assessment to determine clinical endpoints and treatment response, will lead to advancements in our understanding and treatment of adolescent chronic pain. These findings will directly inform the decision of whether to proceed with a large multi-site RCT of GET Living, serving as the basis for potential large-scale implementation of GET Living nationwide.